The Brain And Cranial Nerves Chapter 14 Summary

The Brain and Cranial Nerves
Chapter 14 Notes 14.1 Brain Organization, Protection, and Blood Supply * brain: a portion of the CNS made of neurons and neuroglia * control center for registering sensations and correlating them together and with stored information to make decisions and take action * center for intellect, emotions, behavior and memory * neural tube: brain and spinal cord develop from the ectodermal tube * anterior part expands * inner part constricts to form three regions * primary brain vesicles: prosencephalon, mesencephalon, and rhombencephalon * secondary brain vesicles: formed by the subdivided prosencephalon and rhombencephalon * prosencephalon:
* choroid plexus adds more fluid to the fourth ventricle * CSF enters the subarachnoid space through three openings in the roof of the fourth ventricle * a single median aperture and paired lateral apertures * CSF circulates in the central canal of the spinal cord and in the subarachnoid space around the surface of the brain and spinal cord * CSF is gradually reabsorbed into the blood through arachnoid villi * arachnoid villi: fingerlike extensions of the arachnoid that project into the dural venous sinuses, especially the superior sagittal sinus * arachnoid granulation: a cluster of arachnoid villi * CSF is reabsorbed as rapidly as it is formed by the choroid plexuses * the same rates of formation and reabsorption allow the a constant pressure and volume of CSF 14.3 The Brain Stem and Reticular Formation * the brain stem consists of * medulla oblongata * pons * midbrain Medulla Oblongata * medulla: continuous with the superior part of the spinal cord and forms the inferior part of the brain stem; begins at the foramen magnum and extends to the inferior border of the
* tentorium cerebelli: supports the posterior part of the cerebrum and separates the cerebrum from the cerebellum * shape of cerebellum resembles a butterfly * vermis: central constricted area * cerebellar hemispheres: lateral wings or lobes * each hemisphere consists of lobes separated by deep and distinct fissures * anterior and posterior lobe: govern subconscious aspects of skeletal muscle movements * flocculondular lobe: inferior surface contributes to equilibrium and balance * cerebellar cortex: gray matter in a series of slender, parallel folds called folia * arbor vitae: tracts of white matter that resemble branches of a tree * cerebellar nuclei: gray matter that give rise to axons carrying impulses from the cerebellum to other brain centers * cerebellar peduncles: attach the cerebellum to the brain stem and these bundles of white matter consist of axons that conduct impulses between the cerebellum and other parts of the brain * superior cerebellar peduncles: connects the midbrain to the cerebellum * middle cerebellar peduncles: connects pons to the cerebellum; largest peduncles * inferior cerebellar peduncles: connects the medulla to the